Step-growth polymerization of 10,11-epoxyundecanoic acid. Synthesis and properties of a new hydroxy-functionalized thermoplastic polyester

Abstract Oxidation of undecylenic acid, a derivative of castor oil, affords 10,11-epoxyundecanoic acid ( 5 ). In the presence of a quaternary ammonium or phosphonium bromide as an initiator, monomer 5 undergoes an AB polymerization via nucleophilic ring-opening of the epoxide group with the carboxylic acid moiety to yield high-polymeric hydroxy-functionalized aliphatic polyester ( 6 ). Polymer 6 is a crystalline thermoplastic ( T m  = 97 °C) that exhibits yield stress, break stress and elongation (9.7 MPa, 24.1 MPa and 450%) very similar to those of linear low density polyethylene. However, in contrast to the behavior of the polyolefin and owing to the pendent hydroxyl moieties of 6 , films of the polyester adhere strongly to metallic substrates and have moderately good barrier to oxygen. In addition to physical properties of 6 , the effect of the initiator utilized in the polymerization of 5 on the molecular weight and polydispersity of product 6 is discussed.